In-transit mixing machine drives are used in in-transit mixing machines (e.g., in-transit concrete mixers) in order to set the drum inclined at an angle (α) relative to a horizontal plane in rotational movement with a desired output rotational speed. The essentially cylindrical drum is here connected to the drive at a closed, lower end, i.e., arranged closed to the horizontal plane, and supported in the drive by an output bearing of the drive. At a second end of the drum provided with an opening, the drum is supported so that it can rotate relative to the housing by a second bearing. While the second bearing absorbs only radial forces (e.g., track roller bearing), the output bearing of the drive must absorb both radial and also axial forces. Due to the inclined position of the drum and the contradictory conditions of use (in some cases, non-optimal lubrication, very low rotational speeds, large and sometimes impact-like loads, etc.), the output bearing must have sufficiently large dimensions.
Typically, a double-row pendulum roller bearing is used as the output bearing, because this can receive both large radial forces and also large axial forces. The pendulum roller bearing is installed inclined at an angle (α) relative to a horizontal plane, in order to take into account the corresponding inclination of the drum rotational axis. In addition, a pendulum roller bearing makes it possible to compensate for the angle depending on the design, because dynamic changes in the angle of the drum rotational axis can be compensated.
The dimensioning of such output bearings is performed under the viewpoint that the desired service life is reached for a bearing design under the specified conditions (forces, lubrication, temperature, etc.). The influence of the service life is here realized by the dimensioning (in the sense of “scaling”) of the pendulum roller bearing, which can be demanding in the given installation space.
From DE4034139A1, a drive arrangement for an in-transit concrete mixer is known whose planetary drive has a shaft that transitions into a driven flange and is supported by a pendulum roller bearing relative to a mixer drive housing.
Solutions with pendulum roller bearings for supporting the drum of an in-transit mixing machine are also known from the following publications: DE19829411A1, DE2111073A1, DE2753246A1, DE4314218B4, DE7736479U, and DE8326270U1.
From DE102004038502A1, a drive for driving a drum of an in-transit mixing machine is known, wherein a shaft is supported in the housing by a tapered roller bearing, and the tapered roller bearing has two single-row tapered roller bearings that are spaced apart in the axial direction with the same bore diameter and different outer diameters. A disadvantage in the solution of DE102004038502A1 is that the bearing due to the use of two separate, single-row tapered roller bearings is complicated and expensive and the installation space must be adapted to the different outer diameters.
From EP1705392B1, a double-row pendulum roller bearing for supporting a main shaft of the drive of a wind turbine is known whose two bearing rows have rolling bodies with different lengths and different pressure angles.